"…Intelligent life in
the Universe is an extraordinary and rare, perhaps even unique, phenomenon.
This fact places an especial responsibility on humankind to ensure that this
spark of consciousness does not fade away owing to its unwise actions, but
instead flares into a blazing bonfire that could be observed even from the
remotest regions of our Galaxy."

Iosif S. Shklovskii, Universe,
Life, Mind.

Many leaders of the modern SETI community oppose
the deliberate transmission of messages from Earth to the stars in attempts to
communicate with extraterrestrial intelligence (ETI). Instead, they prefer to
take a passive approach called SETI: merely monitoring optical and radio
wavelengths for messages sent by an ETI. This attitude is interesting in that,
just a few decades ago, SETI was envisioned as a two-way communication process.
In fact, the original acronym for the community was CETI for Communication
with Extraterrestrial Intelligence.

Today, the deliberate transmission of messages to
the stars is often referred to as Active SETI, as opposed,
presumably, to Passive SETI, the monitoring approach described
above. Other terms have been suggested for Active SETI: BETI, for
Broadcast to Extraterrestrial Intelligence, and METI, our preferred
acronym, for Messaging to Extraterrestrial Intelligence.

Several METI attempts have been made over the past
few decades: the famous 1974 Arecibo message; the Pioneer and Voyager
interstellar spacecraft that carry information about Earth for the benefit of
whatever ETI may encounter the spacecraft in the future; and the Invitation
to ETI Web site
where Dr. Allen Tough of the University of Toronto has composed a message
inviting ET, whom, Tough presumes, may be monitoring the World Wide Web, to
contact us.

Furthermore, the authors of this paper have,
collectively, conducted three METI
transmissions:
Cosmic Call 1999, Teen Age Message 2001, and Cosmic Call 2003, all from the
Evpatoria Planetary Radar facility in Ukraine. Like Arecibo, our transmissions include scientific information.
But unlike the Arecibo message, which was composed by a
handful of scientific elites, our transmissions also include personal messages
of thousands of people from around the world. In contrast to many SETI leaders,
we strongly believe in a truly democratic approach to METI: that the people
themselves, not just a handful of elites, should speak for Earth through their
direct participation in METI.

Indeed, public interest in METI is widespread: Our
Cosmic Calls have generated worldwide media coverage. Furthermore, many
rank-and-file SETI enthusiasts appear to support METI: According to an informal
poll on the SETI@home Web site (see http://setiathome.ssl.berkeley.edu/polls.html). As of January 8, 2005, 78% of respondents have answered yes to
the question, Should Earth send a signal for aliens to hear?

Yet many of the elites in the SETI community’s
leadership remain stubbornly opposed to METI. They cite several arguments. We
address three of them here:

1. METI is not scientific

Quite the contrary, our METI transmissions are
conducted under the guidance of scientists and engineers using powerful
planetary radar. The scientific messages included in the transmissions utilize
sophisticated encoding techniques based upon basic mathematics and scientific
concepts.

There are many analogues in the natural and social
sciences to METI. Consider a medical researcher who injects a particular
substance into laboratory mice to see how their biological systems react. Or
consider an economist, a social scientist, who examines how a new government
regulation affects a market system. Or consider an ecologist who studies how
the introduction of a pollutant into the environment affects the living system
in which we all exist. Similarly, we tweak a system, the ETI community in the
Milky Way Galaxy, with METI transmissions in the hope that an ETI will respond,
thus answering one of the most fundamental questions of science: Are we alone?

But METI is not just a science, it is also an art.
Earth's science is the product of the human mind, which in turn is affected by
the cultural and historical influences - and accidents - of human history. The
way an ETI views nature may not conform to our scientific paradigm. So, to
increase the likelihood of effective communication across interstellar space,
we include in our METI transmissions non-scientific messages: text, audio,
video, art, music, etc. For example, Teen Age Message 2001 included the Theremin
Concert for Aliens, possibly the first analog interstellar radio message.

2. METI is risky

Is it possible that the ETI whom we contact is an
evil, imperialistic sort that, upon receiving our messages, will fly to Earth
and gobble us up? We call this the Darth Vader Scenario.

Setting aside the plausibility of physical
interstellar travel, and whether it would be worth it to Mr. Vader to travel to
our neck of the galactic woods, we should recognize that avoiding a risk is
itself risky. Another equally plausible scenario is that the ETI we contact is
a Luke Skywalker who responds to our METI message both by warning us of Lord
Vader's sinister nature, and by telling us what steps we can take to defend
ourselves. Assuming Darth is imperialistic and is exploring the various star
systems of the galaxy, he may eventually find us anyway. Wouldn't we be better
off with Luke's sage advice?

And what of the risk of not learning what we can
from an ETI? Perhaps the knowledge and wisdom an ETI could impart to us would
save us from humanity's self-destructive tendencies, such as nuclear war,
biological warfare, or environmental degradation.

The tendency to focus on the dangers of exploration
is nothing new in human history. Centuries ago, everyone knew that
mariners who sailed too far over the oceans would fall off the edge of the
Earth, or be eaten by sea monsters. Yet humans dared to explore. They took the
risk of encountering the presumed sea monsters - their own version of Darth
Vader - and discovered a new world inhabited by an alien civilization
with alien crops and resources.

3. METI is pointless

This argument holds that CETI, the two-way
communication process of which METI is a part, is too time-consuming. For
example, a Cosmic Call transmission aimed at a star 100 light-years from Earth
will take a century to reach its target star. Assuming ET replies, another
century will elapse before we receive the reply. 200 years far surpasses the
lifetime of any of us alive today.

History is full of examples of people who undertook
great projects to benefit future generations. For example, it often took
several generations of workers to build the great cathedrals of Europe. And in our everyday lives, parents and grandparents
make tremendous sacrifices to ensure their offspring are educated and prepared
to lead happy lives far after the parents and grandparents have passed away.

As Carl Sagan once put it, "For those who have
done something they consider worthwhile, communication to the future is an
almost irresistible temptation, and it has been attempted in virtually every
human culture. In the best of cases, it is an optimistic and far-seeing act; it
expresses great hope about the future; it time-binds the human community; it
gives us a perspective on the significance of our own actions at this moment in
the long historical journey of our species."

In conclusion, we subscribe to one possible
solution to the Fermi Paradox: Suppose each extraterrestrial civilization in
the Milky Way has been frightened by its own SETI leaders into believing that
sending messages to other stars is just too risky. Then it is possible we live
in a galaxy where everyone is listening and no one is speaking. In order to
learn of each others' existence - and science - someone has to make the first
move.